Self surveying portable sensor nodes

Abstract

A self-surveying range includes a base station and a plurality of nodes. Each node has a transmitter, a receiver and a processor and is capable of transmitting a signal encoded with a node identifier, the transmission time. The node can also receive transmitted signals from other nodes. The base station also has a transmitter, a receiver and a processor. The base station is capable of determining its location, transmitting an encoded signal with the transmission time and receiving transmitted signals from said plurality of nodes at a definite time. The base station processor can determine the location of each node from the base station location, the node transmission time and the definite reception time. There is further provided a method for establishing a self-surveying range.

What is claimed is: 
     
       1. A self-surveying range comprising:
 a plurality of nodes, each node having a transmitter, a receiver and a processor and capable of transmitting a signal encoded with a node identifier, the transmission time and receiving transmitted signals from other nodes; 
 a base station having a base station transmitter, a base station receiver and a base station processor, said base station being capable of determining its location, transmitting an encoded signal with the transmission time and receiving transmitted signals from said plurality of nodes at a definite time, said base station processor being capable of determining the location of each node from the base station location, the node transmission time and the definite reception time. 
 
     
     
       2. The system of  claim 1  wherein said base station receiver is capable of receiving a first set of transmitted signals from said plurality of nodes at a definite time at a first determined location, and said base station receiver is capable of receiving a second set of transmitted signals from said plurality of nodes at a definite time at a second determined location, said first and second determined locations and said first and second sets of transmitted signals being utilized by said base station processor for determining the location of each node. 
     
     
       3. The system of  claim 2  wherein said base station includes a global positioning system receiver joined to said base station processor and allows determination of the location of said base station. 
     
     
       4. The system of  claim 1  wherein:
 the self-surveying range is capable of tracking a signal emitter; 
 each of said plurality of nodes at said node receiver is capable of receiving a signal from the signal emitter at a definite time and transmitting the node identifier and the definite reception time to the base station; and 
 said base station receiver is capable of receiving each transmitted node identifier and definite reception time and utilizing the node identifier and definite reception time with the determined location nodes to calculate a signal emitter location. 
 
     
     
       5. The system of  claim 1  wherein said base station processor has a sound velocity profile stored therein and said base station processor is capable of utilizing said stored sound velocity profile to more accurately determine the location of each node. 
     
     
       6. The system of  claim 1  wherein:
 at least one of said nodes has a instruments therein connected to the node processor, said instruments being capable of acquiring sound velocity profile data during deployment and utilizing said node transmitter to transmit sound velocity profile data to said base station for reception by said base station receiver; and 
 said base station processor is capable of utilizing said received sound velocity profile to more accurately determine the location of each node. 
 
     
     
       7. A method for providing a self-surveying range comprising the steps of:
 synchronizing times among a plurality of nodes and a base station; 
 deploying the plurality of nodes, each node being capable of transmitting and receiving a signal; 
 providing the base station in signal communication with said deployed plurality of nodes; 
 obtaining a base station location; 
 transmitting an encoded signal at each node having a transmission time and a node identifier; 
 receiving encoded signals at each node from other nodes in said plurality of deployed nodes; 
 calculating a range between the receiving node and the other node; 
 receiving encoded signals at said base station from said plurality of nodes; 
 calculating a range between said base station and said plurality of deployed nodes; and 
 calculating node locations based on the calculated ranges among the nodes, the ranges between said base station and said plurality of deployed nodes and said base station location. 
 
     
     
       8. The method of  claim 7  further comprising:
 establishing a range residual tolerance between the measured ranges between the nodes and the ranges derived from the calculated node locations; and 
 refining calculated locations of nodes by utilizing the measured ranges between nodes and ranges given by the calculated node locations to give range residuals and dropping measured ranges between nodes until the range residual tolerance is reached. 
 
     
     
       9. The method of  claim 7  wherein:
 receiving encoded signals at said base station from said plurality of nodes comprises receiving encoded signals at said base station from said plurality of nodes at a first base station location; 
 receiving encoded signals at said base station from said plurality of nodes comprises receiving encoded signals at said base station from said plurality of nodes at a second base station location; and 
 calculating node locations based on the calculated ranges among the nodes, the ranges between said base station and said plurality of deployed nodes at said base station first location and at said base station second location. 
 
     
     
       10. The method of  claim 9  wherein said first base station location and said second base station location are different known locations on said base station. 
     
     
       11. The method of  claim 9  wherein said base station is moved from said first base station location to said second base station location. 
     
     
       12. The method of  claim 7  wherein said step of calculating a range between said base station and said plurality of deployed nodes utilizes a sound velocity profile of the environmental water. 
     
     
       13. The method of  claim 12  wherein said sound velocity profile is stored in the base station processor and said base station processor is capable of utilizing said stored sound velocity profile to determine the location of each node. 
     
     
       14. The method of  claim 12  further comprising:
 gathering sound velocity profile data by at least one node during deployment; and 
 transmitting gathered sound velocity profile data to said base station prior to the step of calculating a range between said base station and each said node.